Distilling seawater to fresh water is pretty easy with very little outlay in materials except for the fuel/energy reguired. All you do is boil the water and condense the steam.
I read somewhere that reverse osmosis (the current watermakers available) use three times less energy than distilling. At a cost of $4,000 -$6,000 for a RO watermaker. That buys A LOT of fuel.
I wonder how much distilled water a 25lb/9kg tank of propane, would produce. Any ideas.
Beau

I believe (sorry, no references) that R/O Filtration uses something on the order of 1/8Th to 1/10Th the energy that Distillation uses.
Of course, distillation is a proven technology for water disinfection. Systems can be sized for one person, up to community-sized systems. SOLAR Stills have no moving parts, relying only on the sun for energy, and should last 20 years or more. The cost of materials to build a singleSolar still might be less than $300.
Notwithstanding, I wouldn't want a 212 degree device on my boat (in the tropics).

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Gord May "If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"

I have looked at the solar idea and I just don't think it will work. Not enough output and high set up cost.
Diesel/ kerosene/s propane is still by far the cheapest sourse of energy.
The Still wouldn't have to be very large, I would envisage a small bilge pump, pumping salt water up to a continuously supplied boiler and a condensor with something like a small camping stove to supply the heat, and maybe hang it over the stern of the boat. As I said $4,000-$6,000 buys a lot of camping fuel. Also it would be a lot more reliable than RO's